[tor-bugs] #2385 [Tor Hidden Services]: rendservice.c: cleanup stack stored key material

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#2385: rendservice.c: cleanup stack stored key material
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    Reporter:  cypherpunks         |        Type:  defect             
      Status:  new                 |    Priority:  normal             
   Milestone:  Tor: 0.2.3.x-final  |   Component:  Tor Hidden Services
     Version:                      |    Keywords:  audit              
      Parent:                      |      Points:                     
Actualpoints:                      |  
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Comment(by andrea):

 The following instances of keys and key-derived material on the stack or
 heap occur.  Whenever on the stack, we must be sure they are zeroed before
 the function returns.  Whenever on the heap, zero before they are freed.

  * rendclient.c:
    * rend_client_send_introduction() (line 124)
      * Payload contains hashed key on stack
    * rend_client_refetch_v2_renddesc() (line 624)
      * Descriptor ID on stack
    * rend_client_receive_rendezvous() (line 844)
      * Descriptor cookie and keys on stack
    * rend_parse_service_authorization() (line 1167)
      * Descriptor cookie on heap
  * rendservice.c:
    * rend_service_load_keys() (line 615)
      * Keys allocated on the heap
      * Descriptor cookies on the stack
    * rend_service_introduce() (line 1038)
      * Keys, digest, descriptor cookies on stack
    * rend_service_intro_has_opened() (line 1562)
      * Keys, digest on stack
    * rend_service_rendezvous_has_opened()
      * Descriptor cookie on stack

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/2385#comment:8>
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